Abstract

This paper presents the results of study on the probability distortion. The distortion is studied at two levels: (i) in the decision maker's perception (expressed as subjective judgements), and (ii) in the decision maker's choices (expressed in decision weights). The study examined how the two types of distortion – concerning perception and weights – depend on the way information on probability is presented. Two formats of probability information were distinguished: descriptive (expressed in numbers) and experience.

The results confirmed the hypothesis of lower perceptual distortion of objective probability when the information on payout distribution was presented using the experience-based format than when the information was given as a description. The hypothesis on the lower distortion of probability in decision weights with the experience probability format was not confirmed. An unexpected result was a lower risk seeking with the experience format. This effect seems to be a result of attributing lower weights than with the descriptive format. Furthermore, it appears that the probability distortion in decision weights at least partly results from the distortion in perception.

Keywords